The greatest speech in sports history was delivered on the Fourth of July. It would have been greater if Hillary Clinton delivered it.

Lou Gehrig did the honors that afternoon in 1939. It was at Yankee Stadium. Big retirement ceremony. You probably know the rest of the story.

What you might not know is how experts view the oration. Gehrig’s farewell speech was rated No. 73 on the list of top 100 American speeches of the 20th century. That’s pretty good until you consider the circumstances.

Unlike almost everybody else on the list, Gehrig wasn’t into speechifying. His staff didn’t write his words and test-market applaud lines. In the interest of national harmony on this Independence Day, I won’t make a crack about teleprompters.

All that makes Gehrig’s speech Top-10 material, but it didn’t overly impress the experts. In 1999, “173 leading scholars of American public address” were asked to recommend speeches based on social, political impact and rhetorical artistry.

I’m no leading scholar of American public address, but something ain’t right here. Martin Luther King’s “I Have a Dream,” was No. 1. No argument there, but the overall list was heavily political and feminist.

That was better than Gehrig’s testimony before 61,808 fans at Yankee Stadium?

I’ll admit I’m a dumb sports fan. I first noted the list years ago and figured the experts would eventually sober up and send out a corrected version. The more time passes, the less Americans remember the other speeches.

Gehrig’s resonates because of the way he lived and the way he died. He embodied just about everything admirable in an athlete. Well, he could have been a better interview. But when he wanted to be quotable, he was to the point.

When a New York sportswriter ate a bad hotdog and was given medicine by the Yankees’ doctor, Gehrig said, “A writer sick ... good, I hope he gave the son of a b---- rat poison.”

Other than disliking the media, Gehrig would not have blended into today’s pop-jock culture. He never had to pose for a mug shot. He lived at home until he was 30. He rarely missed a day at work. It never even occurred to him to speak of himself in the third person.

Those qualities manifested themselves on July 4, 1939. Being genuine is at the heart of great speaking.

Like Lincoln’s two minutes at Gettysburg, Gehrig’s speech was also over before most orators would have cleared their throats. It had a memorable catchphrase, a la “Ich Bin Ein Berliner” and “Tear Down That Wall.”

And it had the advantage of being broadcast over the public address system in the very large house that Gehrig’s rotund teammate built. For the past 72 years, that haunting echo has been part of almost every recitation.

It was obvious luck had abandoned him, though few in attendance knew how dire Gehrig’s situation was. As he ambled to home plate, they just knew he wasn’t the same guy who played through broken bones, concussions and illness for 14 straight seasons.

Gehrig’s consecutive game streak had ended two months earlier. The two-time MVP was batting .143. After going hitless the night before, he unassumingly walked over to manager Joe McCarthy before a game in Detroit.

“I’m benching myself, Joe,” he said, “for the good of the team.”

Gehrig was 35 years old. He never played again.

He went to Mayo Clinic and was diagnosed with amyotrophic lateral sclerosis. All that mysterious killer lacked was a name everybody could remember.

A few weeks later the Yankees decided to make July 4 “Lou Gehrig Appreciation Day.” There were testimonials and gifts. Gehrig was already so weak he couldn’t hold the awards presented to him.

He almost had to be prodded to the microphone. For most of his career, his bat had done all the talking when it mattered. Now it was his turn.

There was no way to avoid mentioning the elephant in the stadium, so he started by acknowledging his “bad break.” He quickly pivoted, calling himself not just lucky, but the luckiest man on the face of the earth.

He talked about other people, and how lucky he was to have known them. From owners to managers to teammates to the groundskeepers. He even thanked his mother-in-law for her support.

“So I close in saying that I might have been given a bad break,” Gehrig said, “but I’ve got an awful lot to live for. Thank you.”

Generations of people have thanked him for the inspiration, for showing them how to handle adversity. And he did it in 277 words.

Hillary’s U.N. speech was 2,327 words. And she never played in 2,130 consecutive games.

That shouldn’t have mattered to the experts, and it obviously didn’t. But I wish they’d have been at Yankee Stadium 72 years ago.

I wish they’d seen Babe Ruth come over and hug Gehrig. I wish they’d heard the two-minute standing ovation.

The final thing a great speech needs is impact. Gehrig died less two years after his farewell.

Nothing against the 72 speeches ahead of him, but few of them will echo through the ages like Lou’s.